In the first half of the nineteenth century it was generally believed that reactions of organic compounds proceeded with minimal structural change. This tenet simplified the elucidation of the numerous substitution, addition and elimination reactions that characterized the behavior of common functional groups.
In the 1970s the solderless breadboard (AKA plugboard, a terminal array board) became available and nowadays the term breadboard is commonly used to refer to these.Breadboard is also a synonym for  prototype .Because the solderless breadboard does not require soldering, it is reusable. This makes it easy to use for creating temporary prototypes and experimenting with circuit design.n the 1970s the solderless breadboard (AKA plugboard, a terminal array board) became available and nowadays the term breadboard is commonly used to refer to these.
A toaster works by applying radiant heat directly to a bread slice. When the bread's surface temperature reaches about 310 degrees Farenheit, a chemical change known as the Maillard reaction begins.Sugars and starches start to caramelize -- turn brown -- and to take on intense flavors. That's toast. 9 0 0 - 1 9 2 0. As stated above, toast is made by applying radiant heat to a slice of bread. This is easily done with fire, but creating an electrical device to toast bread presented quite a challenge.